Development of a finger-stick white blood cell (WBC) count assay method using a disposable test strip and a palm-size reader is proposed. The method will estimate the WBC count in minutes in a non-laboratory setting such as the patient's home. Preliminary data obtained with manually assembled prototypes have demonstrated the feasibility of the proposed method. A simple point-of-care (POC) method for measuring a WBC count will give healthcare providers a portable means of monitoring their cancer patients undergoing chemotherapy. Currently, there is no inexpensive and accurate method available. The proposed device will increase chemotherapy scheduling efficiency by allowing healthcare providers to obtain a WBC count before the patient comes in for therapy. This will in turn reduce health costs. POC applications for the proposed device have a potential worldwide market of $160 million annually. In Phase II, we propose to scale-up the device, develop a palm-size reader, thoroughly test the assay system, and prepare for a clinical trial in Phase IIl .